using UnityEngine;
using UnityEditor;
using UnityEditor.Animations;
using UnityEditorInternal;
using System.Collections.Generic;
using AnimatorController = UnityEditor.Animations.AnimatorController;

public class AnimatorLinkWindow : EditorWindow
{
    private AnimatorController animatorController;
    private List<AnimationClip> clips = new List<AnimationClip>();
    private ReorderableList reorderableList;

    // 排版参数
    private int statesPerColumn = 5;
    private float horizontalSpacing = 200f;
    private float verticalSpacing = 80f;

    [MenuItem("Tools/Animator Link Window")]
    public static void ShowWindow()
    {
        GetWindow<AnimatorLinkWindow>("Animator Linker");
    }

    private void OnEnable()
    {
        reorderableList = new ReorderableList(clips, typeof(AnimationClip), true, true, true, true);

        reorderableList.drawHeaderCallback = (Rect rect) =>
        {
            EditorGUI.LabelField(rect, "Animation Clips (可拖拽排序)");
        };

        reorderableList.drawElementCallback = (Rect rect, int index, bool isActive, bool isFocused) =>
        {
            clips[index] = (AnimationClip)EditorGUI.ObjectField(
                new Rect(rect.x, rect.y, rect.width, EditorGUIUtility.singleLineHeight),
                clips[index], typeof(AnimationClip), false);
        };

        reorderableList.onAddCallback = (ReorderableList list) =>
        {
            clips.Add(null);
        };

        reorderableList.onRemoveCallback = (ReorderableList list) =>
        {
            clips.RemoveAt(list.index);
        };
    }
    private Vector2 scrollPos;
    private void OnGUI()
    {

        GUILayout.Label("Animator Controller", EditorStyles.boldLabel);
        animatorController = (AnimatorController)EditorGUILayout.ObjectField(
            "Controller", animatorController, typeof(AnimatorController), false);

        GUILayout.Space(10);

        // 排版参数输入框
        statesPerColumn = EditorGUILayout.IntField("每列多少个状态", statesPerColumn);
        horizontalSpacing = EditorGUILayout.FloatField("同列水平间隔", horizontalSpacing);
        verticalSpacing = EditorGUILayout.FloatField("列与列垂直间隔", verticalSpacing);
        // 开始滚动区域
        scrollPos = EditorGUILayout.BeginScrollView(scrollPos);
        GUILayout.Space(10);

        reorderableList.DoLayoutList();
        EditorGUILayout.EndScrollView(); // 结束滚动区域

        Rect dropArea = GUILayoutUtility.GetRect(0.0f, 50.0f, GUILayout.ExpandWidth(true));
        GUI.Box(dropArea, "拖拽 AnimationClip 到这里 (支持多选)");
        HandleDragAndDrop(dropArea);
        
        GUILayout.Space(10);
        if (GUILayout.Button("生成状态并连线"))
        {
            GenerateStatesAndTransitions();
        }
        
    }

    private void HandleDragAndDrop(Rect dropArea)
    {
        Event evt = Event.current;
        if (!dropArea.Contains(evt.mousePosition)) return;

        switch (evt.type)
        {
            case EventType.DragUpdated:
            case EventType.DragPerform:
                if (DragAndDrop.objectReferences.Length > 0)
                {
                    DragAndDrop.visualMode = DragAndDropVisualMode.Copy;

                    if (evt.type == EventType.DragPerform)
                    {
                        DragAndDrop.AcceptDrag();
                        foreach (Object obj in DragAndDrop.objectReferences)
                        {
                            if (obj is AnimationClip clip)
                            {
                                clips.Add(clip);
                            }
                        }
                        Debug.Log($"已添加 {DragAndDrop.objectReferences.Length} 个动画");
                    }
                }
                Event.current.Use();
                break;
        }
    }

    private void GenerateStatesAndTransitions()
    {
        if (animatorController == null)
        {
            Debug.LogError("请先指定 AnimatorController");
            return;
        }
        if (clips.Count == 0)
        {
            Debug.LogError("请至少添加一个 AnimationClip");
            return;
        }

        var rootStateMachine = animatorController.layers[0].stateMachine;

        // 判断是否已有状态
        if (rootStateMachine.states.Length > 0)
        {
            int option = EditorUtility.DisplayDialogComplex(
                "已有状态",
                "当前 AnimatorController 已经有状态，是否清空后重新生成？",
                "清空并重新生成",
                "从尾部继续添加",
                "取消"
            );

            if (option == 0)
            {
                // 清空
                rootStateMachine.states = new ChildAnimatorState[0];
            }
            else if (option == 2)
            {
                // 取消
                return;
            }
            // option == 1 表示从尾部继续添加，不清空
        }

        AnimatorState prevState = null;
        if (rootStateMachine.states.Length > 0)
        {
            // 如果已有状态，从最后一个开始连线
            prevState = rootStateMachine.states[rootStateMachine.states.Length - 1].state;
        }

        int existingCount = rootStateMachine.states.Length;

        for (int i = 0; i < clips.Count; i++)
        {
            var clip = clips[i];
            if (clip == null) continue;

            // ✅ 计算偏移量：已有状态数量 + 新的索引
            int index = existingCount + i;
            int col = index / statesPerColumn;
            int row = index % statesPerColumn;

            var state = rootStateMachine.AddState(
                clip.name,
                new Vector3(col * horizontalSpacing, row * verticalSpacing, 0)
            );
            state.motion = clip;

            if (prevState != null)
            {
                var transition = prevState.AddTransition(state);
                transition.hasExitTime = true;
                transition.exitTime = 1f;
                transition.duration = 0f;
            }

            prevState = state;
        }


        Debug.Log("生成完成：已按顺序创建状态并排版连线");
    }



}